JP3081855B2 - Pulp beating method for photographic paper - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for beating pulp of a photographic printing paper base. More specifically, the present invention relates to a method of beating pulp for making a paper substrate having excellent smoothness of photographic printing paper, cuttability, and resistance to penetration from an edge.

[0002]

2. Description of the Related Art In recent years, as a support for photographic printing paper, a water-resistant resin-coated paper in which both sides of a paper substrate are coated with a water-resistant resin has been used instead of the conventional baryta paper.
It is effective for speeding up development processing and dimensional stability, and at present has occupied most of photographic printing paper supports. Unlike the conventional baryta paper, such a water-resistant resin-coated support is printed without being ferro-typed, and the smoothness of the print surface depends on the smoothness of the support used. The smoothness of the surface of the support depends on the smoothness of the paper substrate used. Therefore, in order to obtain a photographic paper having a smooth surface, it is necessary to manufacture a paper substrate having good smoothness.

[0003] The roll-shaped photographic paper is subjected to a printing process and a developing process when producing a photographic print, and then cut into a predetermined print size. Generally, this cutting operation is automated, and a required cutting mark is applied to the roll-shaped photographic paper by means such as a hole punch before cutting. In this hole punching, if the cuttability is poor, small holes are not formed sharply by hole punching, and pulp fibers around the holes extend into the holes. The small holes filled by the whiskers are not detected by the photoelectric tube as cutting marks, and the automatic cutting operation of the roll-shaped photographic printing paper becomes impossible.

Further, the speed of processing of water-resistant photographic printing paper has been increasing, and accordingly, the processing conditions have become more severe. Although the treatment liquid is prevented from penetrating from the coated surface by coating with the water-resistant resin, the water-resistant resin is not coated,
The penetration of the processing solution from the edge cannot be prevented. The permeated treatment liquid is not sufficiently removed in the ordinary washing step,
Changes color to brown upon heating or aging, and significantly reduces print quality.

[0005] For the above reasons, the support for photographic printing paper is required to have excellent smoothness, cuttability, and resistance to penetration of the processing solution from the edge. Various proposals have been made for a method for making a paper substrate of photographic printing paper having such characteristics. For example, JP-A-58-6803
No. 7 proposes a desirable distribution of fiber length by a sieving method of pulp fibers obtained by beating pulp in order to solve the cuttability. Tokiko Sho 59-4
No. 2295 proposes that raw pulp be specified by its photochemical properties in order to solve the smoothness. However, the pulp-related technology disclosed in the publication alone cannot simultaneously satisfy the object of the present invention, namely, smoothness, cuttability, and treatment liquid penetration resistance. Also,
Japanese Patent Publication No. 56-54628 discloses a method in which a sizing agent and a paper strength enhancer are added at a predetermined ratio to base paper in order to improve cuttability.
Not listed.

Japanese Patent Application Laid-Open No. 63-256788 discloses a method for beating papermaking pulp to be used as a paper substrate for the purpose of improving smoothness, cuttability and rigidity. This publication stipulates only the ratio of the blade width to the groove width of the disk shape of the double disk lifter which can obtain the required beating in one step. In general, there are many factors that affect the beating situation. The number of revolutions of the double disk refiner, the pulp slurry concentration, the shape of the blade, the shape of the pulp fiber, and the like cannot be used to determine the overall beating situation.

[0007]

SUMMARY OF THE INVENTION The present invention is based on a proper beating situation incorporating various factors that affect beating.
An object of the present invention is to provide a method for beating pulp for making a photographic printing paper substrate, which has simultaneously improved smoothness, cuttability, and resistance to penetration of the developing solution from the edge.

[0008]

According to the present invention, a method for beating pulp of a photographic printing paper substrate comprises connecting two types of beating stages of a double disc refiner in series, and having a ratio I / N expressed by the following equation at the front stage. Is a method of beating pulp characterized by beating using 1 to 30 beating stages, followed by beating using a beating stage having a ratio I / N of less than 1 in the subsequent stage. N = (C / F) × 10 -10 I = (P / C) × 10 6 C = 8π 2 GDqC F ln 3 ω (1 + 2tanφ r) (R 2
_{^{3 -R 1 3) / 3w (}} l + D) ( where, I is the impact strength, N is the impact number, C
Is the C factor, F is the pulp passing rate [Kg / S], P is the effective power [W], C _F is the pulp concentration [ weight ratio ], D is the depth of the groove of the double disc refiner [m] , q is water Density [kg / m ³ ], G is the groove width [m] of the double disc refiner , l is the fiber length of the pulp to be beaten [m] , n is the number of blades per unit of the double disc refiner [m ^{− 1} ] , ω is the angular velocity [S ^-1 ], φ _r is the angle [rad] of the blade shown by equation 2, R ₁ is the inner diameter [m] of the blade ,
R ₂ is the outer diameter of the blade [m], w is the roughness of the pulp fiber to be beaten [Kg / m]. In addition, the effective power [W] is a value obtained by subtracting the power for circulating the pulp slurry without applying a load by separating the disk sufficiently from the power applied during the beating operation. The pulp concentration [ weight ratio] is the weight ratio of pulp to pulp slurry.

[0009]

## EQU2 ## φ _r = (φ ₁ + φ ₂ ) / 2 (where φ ₁ and φ ₂ are the angle between the blade-shaped straight line and the blade)

Hereinafter, the present invention will be described in detail. Although several theories have been proposed for beating, Ker is a theory that incorporates various beating factors and describes the beating situation.
There is the theory of Eskes, R, J. ("Nordic
Pulp and Paper Research Jou
r nal ”; 1/11990), according to which
Factors that represents the beating conditions, double disc refiner, the shape of the blade, such as a conical refiner, the rotational speed, the concentration of the pulp, the fiber length of the pulp to be beaten, the roughness of the pulse <br/> flop being beaten, the density of water And so on. The calculated value C from these is called the C factor. The ratio of the C factor to the pulp passing amount F, C / F, is 10 ⁻¹⁰ , and the effective power P, the ratio of the C factor, P / C, 10 ^6, is I.
Then, the degree of cutting and fibrillation of the beating stage can be represented by these ratios I / N.
The higher the degree of I / N, the higher the degree of cutting.

The present inventor has studied a pulp beating method suitable for a paper substrate of photographic printing paper coated with a water-resistant resin. As a result, the beating steps of two types of double disc refiners were connected in series, and In addition, beating is performed using a beating stage having a ratio I / N of 1 to 30 and then beating using a beating stage having a ratio I / N of less than 1 to obtain smoothness, cuttability, and
It has been found that a photographic printing paper substrate having excellent resistance to developer penetration from the edge can be made.

The photographic paper substrate made from pulp beaten using only a beater stage having a ratio I / N of 1 to 30 has improved smoothness and cuttability, but has a reduced internal bond strength. Due to the decrease in basic strength and the resulting deterioration in penetration resistance from the edge of the developing solution, the product becomes an obstacle and cannot be used. The photographic printing paper substrate made using pulp beaten using only a beating stage having a ratio I / N of less than 1 has improved strength and permeation resistance from the edge of the developing solution, but has improved smoothness and ratio. The cutting property deteriorates, and it becomes an obstacle as a product and cannot be adopted.

In the beating method in which the beating stages of the two double disk refiners are connected in series, the ratio of I
Beating using a beating stage where / N is less than 1, and then the ratio I / N
Is beaten using 1 to 30 beating stages,
Due to the softening of pulp fibers, etc., sufficient cutting and beating performance is not exhibited, and smoothness and cuttability cannot be improved. Further, the photographic printing paper paper base obtained by mixing the pulp slurry beaten using a beating stage having a ratio I / N of 1 to 30 and the pulp slurry beaten only in a beating stage having a ratio I / N of less than 1 is smooth. Properties, cuttability, and penetration resistance of the developing solution from the edge are not improved and cannot be adopted.

The shape of the blade of the double disc refiner used in the present invention can be selected from commonly used blades. For example, when the depth of the groove is from 0.003 to 0.
008m, groove width 0.002 to 0.007m, number of blades 70 to 250 / m, blade angle 0.12 to 0.
Using a blade of 35 rad, about the amount of pulp passing,
From 0.2 to 1.6 kg / s, the pulp concentration from 0.025 to 0.06, and the rotational speed of the double disc refiner, the angular velocity from 5 to 2
From among 5r / s, the effective power is also the ratio I / N
Is selected so that the combination of the factors satisfies the target condition.

Each beating stage used in the present invention may be a single beating stage, but may be a multi-unit set if the conditions are satisfied. The beaten pulp may be mixed and used under different conditions in two stages in series within the scope of the present invention. It may be circulated. Further, the number of stages may be increased. The raw pulp used in the present invention is selected from bleached pulp such as bleached kraft pulp and bleached sulphite pulp.

[0016]

The present invention will be described below with reference to Examples 1 and 2 and Comparative Examples 1 to 4. A mixed pulp of 50 parts by weight of bleached hardwood kraft pulp and 50 parts by weight of bleached softwood sulphite is used as a raw material pulp to a concentration of 0.04. did. In Comparative Example 4, the pulp slurries beaten in only one stage under different conditions so as to satisfy the conditions of and were mixed. The raw pulp had a roughness of 0.0000001 Kg / m, and the average fiber length of the pulp was 0.000075 m.

Among the beating conditions, regarding the shape of the blade,
The first stage has a blade width of 0.0025 m and a groove width of 0.0025 m , and the second stage has a blade width of 0.0025 m and a groove width of 0.0025 m .
The target ratio I / N was adjusted by adjusting the number of revolutions, the amount of passage, and the load power using a 28 m length. The paper was made to 180 g / m ² and 175 μm by a fourdrinier machine. After the paper making, the paper substrate was coated with a polyethylene resin by an extrusion coater at a surface of 30 g / m ² (mirror finish) and a back of 30 g / m ^2.
and m ² is applied. 10% titanium oxide was kneaded into the surface resin layer to improve the sharpness of the image. Then a support for photographic paper coated with a port triethylene resin was photographic paper coated with a photographic emulsion.

Photographic paper is SRP2014 (made by FC)
And subjected to each evaluation. For the cut resistance comprehensively fuzz degree of holes when the fuzz degree and hole punching of the cut surface obtained by cutting the print size by a roll cutter PC505K (manufactured by Noritsu), and 1 with less fuzz, fluff
For those with a slight rise, set to 2
Grading was performed , with 3 being unbearable . Regarding the smoothness , the print surface was visually observed to be 1 for good smoothness, 2 for slightly good smoothness, and poor for smoothness.
Ku, was carried out for 3 and grade with those that do not withstand practical use.
The penetration resistance from the edge of the treatment liquid, SRP201
4 Observe the edge of the print after processing under an ultraviolet light and measure the penetration depth .
No problem as a product, exceeding 0.30 mm, 0.50
mm or less, a level that is slightly bad but has no problem as a product
However, if it exceeds 0.50 mm, the penetration depth is poor,
There is a problem in quality and practicality is lost.

[0019]

[Table 1]

[0020]

The pulp beaten by the method of the present invention has been subjected to moderate cutting and fibrillation beating, and the photographic printing paper base made using this pulp slurry has good formation. Therefore, it has good smoothness, excellent cuttability, and excellent penetration resistance from the edge of the treatment liquid.

[Brief description of the drawings]

FIG. 1 is a schematic view (plan view) showing the shape of a blade used in a double disc refiner.

[Explanation of symbols]

1 Double Disc Refiner Blade 2 Double Disc Refiner Groove φ ₁ , Angle between Plate Sector Straight Line and Blade φ ₂ Plate Sector Straight Line and Blade Angle R ₁ Inner Diameter of Plate R ₂ Outside Diameter of Plate

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G03C 1/775 D21D 1/30 D21H 27/00

Claims (1)

(57) [Claims] 1. A refining stage of two types of double disc refiners is connected in series, and a beating stage using a beating stage having a ratio I / N of 1 to 30 as shown in the following formula is used in a preceding stage, and then, a ratio I / N is shown in a subsequent stage.
A method for beating pulp on a photographic printing paper substrate, wherein the pulp is beaten using a beating stage having a ratio of / N less than 1. N = (C / F) × 10 -10 I = (P / C) × 10 6 C = 8π 2 GDqC F ln 3 ω (1 + 2tanφr) (R
_{^{2 3 -R 1 3) / 3w}} (l + D) ( where, I is the impact strength, N is the impact number, C
Is the C factor, F is the pulp throughput [Kg / S], P is the effective power [W], C _F is the pulp concentration [ weight ratio], D is the depth of the groove of the double disc refiner [m] , q is water Density [kg / m ³ ], G is the groove width [m] of the double disc refiner , l is the fiber length of the pulp to be beaten [m] , n is the number of blades per unit of the double disc refiner [m ^{− 1} ] , ω is the angular velocity [S ^-1 ], φ _r is the angle [rad] of the blade shown by the equation ₁ , R ₁ is the inner diameter [m] of the blade,
R ₂ is the outer diameter of the blade [m], w is the roughness of the pulp fiber to be beaten [Kg / m]. 1) φ _r = (φ ₁ + φ ₂ ) / 2 (where φ ₁ and φ ₂ are the angle between the fan-shaped straight line and the blade)